05000346/FIN-2016001-07
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Finding | |
|---|---|
| Title | Licensee-Identified Violation |
| Description | Licensee engineering and operations personnel performed surveillance test DBNE03214, Moderator Temperature Coefficient Measurement by Rod Swap, on October 31, 2015, to meet the requirements of TS Surveillance Requirement 3.1.3.2. Following completion of the test and analysis of the test data, licensee engineering personnel initiated CR 2015-14893 to document that the extrapolated moderator temperature coefficient was more negative than the limit specified in the plants Core Operating Limits Report (COLR). While licensee personnel correctly evaluated that operation of the unit could continue for the time being since the current moderator temperature coefficient value was within specifications, they failed to correctly interpret the entire Note associated with TS Surveillance Requirement 3.1.3.2. This Note required, in part, that the licensee calculate the minimum boron concentration at which the moderator temperature coefficient was projected to exceed its lower limit, and shutdown the unit prior to reaching this boron value. On January 27, 2016, licensee engineering and operations personnel identified that they had misinterpreted the Note associated with TS Surveillance Requirement 3.1.3.2, and a minimum RCS boron concentration value should have been established. With measurement uncertainties, a minimum RCS boron value of approximately 9.8 ppm [parts per million] was calculated by licensee engineering personnel and provided to plant operators as the minimum RCS boron limit. At that time, RCS boron had been reduced to just 16 ppm as the unit approached the normal end of the current operating cycle. Technical Specification 5.4.1(a) requires the licensee to establish, implement, and maintain applicable written procedures for the safety-related systems and activities recommended in RG 1.33, Revision 2, Appendix A. Section 2(g) of RG 1.33, Revision 2, Appendix A, requires procedures for operation of the reactor at power and process monitoring. Contrary to these requirements, the licensee failed to properly prepare and implement technically adequate written procedures and instructions for the management of RCS boron concentration. Specifically, from October 31, 2015, through January 27, 2016, operational guidance provided to the on-watch operating crews contained no minimum RCS boron value, and during this time crews were effectively attempting to reduce RCS boron concentration to zero ppm, if possible, in preparation for the units 2016 RFO. The objective of the Barrier Integrity Cornerstone of Reactor Safety is to provide reasonable assurance that physical design barriers (fuel cladding, RCS, and containment) protect the public from radionuclide releases caused by accidents or events. A key attribute of this objective involves maintaining design control parameters to protect the integrity of the plants nuclear fuel (e.g., core design analysis parameters associated with the COLR and Cycle 19 Reload Analysis, etc.) In accordance with NRC IMC 0612, Power Reactor Inspection Reports, Appendix B, Issue Screening, the inspectors determined that the violation was of more than minor significance in that it had a direct impact on this cornerstone objective. Specifically, the failure to have established a minimum RCS boron concentration as directed by the Note associated with TS Surveillance Requirement 3.1.3.2 could have resulted in operations personnel reducing boron concentration to the point where the plant was operating in an unanalyzed condition, possibly outside of established accident and safety analyses. Using NRC IMC 0609, Appendix A, The Significance Determination Process for Findings At-Power, Exhibit 3, Barrier Integrity Screening Questions, the inspectors determined that consultation with the NRC Region III SRA was necessary to establish the violations safety significance. Following discussions with the SRA, the inspectors determined that the violation was of very low safety significance (Green), since the RCS boron concentration never was decreased below the 9.8 ppm limit. The licensee had entered this issue into their CAP as CR 201601245. Licensee corrective actions included the immediate cessation of all RCS boron dilution/removal activities, the establishment of a minimum RCS boron concentration as an operational limit, and the performance of a formal causal evaluation. |
| Site: | Davis Besse  |
|---|---|
| Report | IR 05000346/2016001 Section 4OA7 |
| Date counted | Mar 31, 2016 (2016Q1) |
| Type: | NCV: Green |
| cornerstone | Barrier Integrity |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | D Kimble J Cameron T Briley L Alvaredo |
| Violation of: | Technical Specification - Procedures Technical Specification |
| INPO aspect | |
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Finding - Davis Besse - IR 05000346/2016001 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Davis Besse) @ 2016Q1
Self-Identified List (Davis Besse)
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